TABLE 4 Percent of Variance in Birth Rates Explained by Representative Socioeconomic Variabales for Twenty-Five Countries in the Latin American Region, Circa 1960-1964 Percent Variance in Birth Rates Explained by Regression Variable (x) Zero Order'1 Correlations Linear:'3 (a + fix) Single Asymptotic: (a + &PX) 1. Percent population in places 20,000 or more -0.75 55 61 2. Percent of economically active males not in agriculture -0.85*** 71 74 3. Percent literate among population 15+ -0.71 47 77 4. Telephones per 1 ,000 population _0.94*** 87 87 5. Hospital beds per 1,000 population -0.83*** 68 72 6. Newspaper circulation per 1,000 population -0.80*** 62 63 7. Female expectation of life at birth (CQ) -0.76 55 59 aAll values statistically significant at 1 percent level, starred items at 0.1 percent level. All R*- values adjusted downward to correct for degrees of freedom. tion (literacy), of general infrastructure (telephones), of health services (hospital beds), of communication (newspapers), of mortality (expectation of life for females at birth), and the birth rate. The birth rates are official rates accepted as reasonably complete by the United Nations or as estimated by the United Nations agencies from census information for roughly the years 1960-64. These data show a high level of association between the birth rate and these selected measures of development. Collectively these variables explain some 90 percent of the variance in birth rates in Latin America. Although tills is a statistical measure of association, rather than a direct causal explanation, it confirms the view that levels of the birth rate are closely linked to development. It will be noted that these measures relate especially to social and communication variables in which progress is being made in most countries of the less developed world. The relation of birth rates to strictly economic measures, such as per capita income and average annual growth of GNP, is morea single group. However, when the analysis is confined to each of the several major cultural regions, more consistent patterns emerge.